Back up above-ground, trek across the surreal terrain that resembles a moon crater and examine the different types of Hawaiian lava: pahoehoe, which has a smooth and ropey surface, and a'a, which resembles stirred up brownies.

The upper flow unit is well exposed in the Prospect Park quarry and is made up of three types of lava flow structures: massive, columnar basalt, subaqueous, pahoehoe flow lobes, and bedded pillow lava.